We report ultra-low intrinsic magnetic damping in Co25Fe75 heterostructures, reaching the low 10−4 regime at room temperature. By using a broadband ferromagnetic resonance technique, we extracted the dynamic magnetic properties of several Co25Fe75-based heterostructures with varying ferromagnetic layer thickness. By estimating the eddy current contribution to damping, measuring radiative damping and spin pumping effects, we found the intrinsic damping of a 26\,nm thick sample to be \alpha_{\mathrm{0}} \lesssim 3.18\times10^{-4}.Furthermore,usingBrillouinlightscatteringmicroscopywemeasuredspin−wavepropagationlengthsofupto(21\pm1)\,\mathrm{\mu m}ina26nmthickCo_{\text{25}}Fe_{\text{75}}$ heterostructure at room temperature, which is in excellent agreement with the measured damping.
@article{arxiv.1904.11321,
title = {High Spin-Wave Propagation Length Consistent with Low Damping in a Metallic Ferromagnet},
author = {Luis Flacke and Lukas Liensberger and Matthias Althammer and Hans Huebl and Stephan Geprägs and Katrin Schultheiss and Aleksandr Buzdakov and Tobias Hula and Helmut Schultheiss and Eric R. J. Edwards and Hans T. Nembach and Justin M. Shaw and Rudolf Gross and Mathias Weiler},
journal= {arXiv preprint arXiv:1904.11321},
year = {2019}
}